Ladder



March 13, 1956 l c, FU M 2,738,120

LADDER Filed May 19, 1952 1 J FE :Z-Tq

,- Mum i v 3 25 24 i 1 H 27 d/ I [HIH INVEN TOR. JinPe-o C. FuHR/Mn/v flrromveys United States Patent LADDER Jared C. Fuhriman, Alhambra, Calif.

Application May 19, 1952, Serial No. 288,631

4 Claims. (Cl. 228-23) This invention relates to an improvement in ladders, and more particularly to a ladder designed primarily to be manufactured from metal channels hinged to permit folding of the ladder for transportation and storage but provided with a locking mechanism to securely lock the folding sections into alignment when in use.

While folding ladders of one form or another have hitherto been proposed having a dogging mechanism which locks the folding sections in alignment when in use, the present invention presents a greatly simplified form of such a ladder in which the dogging mechanism is securely held in position to lock the sections in alignment by gravity and which can thus not become accidently displaced and permit the ladder to jackknife with possible disastrous results to the user. In other words, this invention presents such a folding ladder which in use fails safe.

It is accordingly one object of this invention to provide a ladder which may be folded for transportation or storage and unfolded to present a full length ladder, the sections of which are securely held in alignment when in use.

It is another object of this invention to provide a ladder of the type described which is simple and economical of construction.

The invention is characterized by the fact that a ladder is constructed of sections of channel shaped metal, preferably of aluminum, having the sections hinged together and in which are placed fixed sections of wood or metal in which are journalled or otherwise fixed the cross bars and also sliding sections of wood or metal carrying one or more cross bars adapted to slide from one section partially into another section when in alignment and in use to lock the sections together.

These and other objects, features and advantages of the present invention willbe apparent from the annexed specification in which:

Figure 1 is a perspective elevation of my improved ladder showing the sliding section in locked condition ready for use.

Figure 2 is a perspective view of the ladder as it would appear when the sliding sections are moved up above the hinged section so as to ready it for folding.

Figure 3 is a side elevation showing the ladder folded.

Figure 4 is a vertical section of a portion of the ladder taken on the line 4-4 of Figure 1 showing the sliding section in locked condition.

Figure 5 is a cross section taken on the line 5-5 of Figure 4.

Figures 6 to 12 show modifications in fabrication of my improved ladder.

Referring now more particularly to the drawings, and particularly to Figures 1 through 5 thereof, the ladder is shown as comprising a plurality of channel shaped sections 20 preferably formed of aluminum in which there are securely fixed sections 21 of wood or metal, rectangular in shape, and in which there are affixed one or more cross bars or steps 22. Within the channels 20 there are "ice also disposed freely slidably sections 23 generally similar in construction to the members 21 and also carrying one or more cross bars or steps 24.

The sections 20 are joined together by a plurality of hinges 25 placed alternately on the front and rear of the latter, as clearly shown in Figures 1 and 2, to permit the ladder when folded to be stacked as shown in Figure 3.

When the ladder is unfolded and the sections 20 are in alignment, the sections 23 may slide in the channels formed by the sections 20 from the position shown in Figure 1 wherein a portion of each section 23 will overlie the junction of the hinges 25 and thus lock the ladder in alignment. It will be noted that the sections 23 will automatically take such locking position under the force of gravity and no other latching mechanism is required. Figure 2 shows the position of the ladder wherein the sections 23 have been raised, presumably by hand, into a condition to permit the folding of the ladder at the junction of the hinges 25.

It is obvious that thesliding members 23 may take a variety of forms. There is shown in Figure 5 a cross section'in which the member 23 takes a form of a rectangular piece of wood in which a round cross bar 24 is dowelled. In Figure 6, the construction is the same with the exception that the sections Zlia are in the form of metallic Ts rather than mere channels. Figure 7 shows a still alternate construction in which the cross bars 24:! are of metal welded or otherwise secured to the T 20a. The sliding sections 23 1 are on the back side of the member Zita and serve merely to lock or unlock the sections without moving the cross bars 24a. In turn flange 26 is provided to hold the sections 23a in place.

Referring to Figure 8, another modification is shown differing from Figure 5 only in the flange 27. Referring to Figure 9, there is illustrated another alternate form of the invention dilfering from Figure 5 only in that the cross bars 24b are rectangular in shape.

Referring to Figure 10, there is shown a modification in which the sliding members 23!) are themselves channel shaped sections of metal to which the cross members 24c are welded or otherwise secured. Figure 11 illustrates a modification of the cross bar 24d showing the same as having a rectangular cross section. Figure 12 illustrates a final embodiment in which the channels 200 have the cross bars 24:: welded or otherwise secured thereto and the sliding members 23c serve merely as locking members held in the channels by the flanges 28.

While there has been described what are at present considered preferred embodiments of the present invention, it will be appreciated by those skilled in the art that various changes and modifications can be made therein without departing from the essence of the invention and it is intended to cover herein all such changes and modifications as come Within the true spirit and scope of the appended claims.

I claim:

1. A folding ladder comprising: a plurality of pairs of channel shaped members hinged together end to end the open side of each member of said pairs facing that of the other member; sections fixed in said channels and mounting cross-bars; sections slidably mounted in said channels and movable from a position Wholly in one of said channels to a position overlying the junction of two of said channels, when aligned end to end, to lock said channels in aligned position; each of said movable sections being joined to the movable section in the opposite channel-shaped member by two cross-bars whereby each of such movable sections, its associated opposed movable section and said two cross-bars move as a unit to locking or unlocking position.

2. A folding ladder comprising: a plurality of pairs of channel shaped members hinged together end to end the openisideof each member of .said pairs facing that of the other member; sections fixed in said channels and mounting cross-bars; sections slidably mounted in said channels and movable from a position Wholly in one of said channels to a position overlying theijunction of two of said channels, when aligned end to end, to lock said channels in aligned position, said slidably mounted sectionslmountingone or more cross-bars fixed therein and in, the movable section in the opposite channel-shaped member whereby each of said movable sections, its associated opposed movable section and said one or more cross-bars move as, a unit to locking or unlocking position. 3. A, folding ladder comprising a plurality of pairs of channel. shaped members hinged together end to end the open. side of each member of said pairs facing that of theother member; sections fixed in saidchannels and mounting cross-bars; sections slidably mounted in said channels and movable from a position wholly in one of said channels to a position overlying the junction of two of said channels, when aligned end to end, to lock said channels in aligned position; said channels being unobstructed so that said slidably mounted sections are free to be urged under the force of gravity into locking position when said channels are aligned in upright position; each of said movable sections being joined to the movable section in the opposite channel-shaped member by two cross-bars whereby each of such movable sections, its associated opposed movable section and said two crossbars move as a unit to locking or unlocking position.

4. A folding ladder comprising: a plurality of pairs of channel shaped members hinged together end to end the open side of each member of' said pairs facing that of the other member; sections fixed in said channels and mounting cross-bars; sections slidably mounted in said channels and movable from a position wholly in one of said channels to a position overlying the junction of two of said channels, when aligned end to end, to lock said channels in aligned position; said slidably mounted sections mounting one or more cross-bars fixed therein and in the movable section in the opposite channel-shaped member whereby each of said movable sections, its associated opposed movable section and said one or more cross bars move as a unit to locking or unlocking position; said channels being unobstructed so that said slidably mounted sections are free to be urged under the force of gravity into locking position when said channels are aligned in upright position.

References Cited in the file of this patent UNITED STATES PATENTS 2,192,830 Gerdes Mar. 5, 1940 2,618,427 Langley et a1. Nov; 18, 1952 FOREIGN PATENTS 823,096 France Oct. 11, 1937 

